Carbureter.



W. SCOTT. UARBURETER. APPMUATIDN FILED JULY 1909.

Patented 0@n.17,1911.

1 1 'I' ne 0*/ 3 1 MN Q UNITED STATES PATENT OFFICE.

WILLIAM SCOTT, 0F MEDFORD, MASSACHUSETTS, ASSIGNOR TO SCOTT MANUFACTURING COMPANY, A CORPORATION 0F MASSACHUSETTS.

CARBURETER.

Specification of Letters Patent,

Patented Oct. 17, 1911.

Application tiled July 8, 1909. Serial No. 506,493.

To all whom it may concern:

Be it known that I, WILLIAM Soo'r'r, a citizen of the United States, residing; in Medford, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Carbureters, of which the following description, in connection with the accompanying drawings, is a inieciicu` tion, like letters on the drawings representinlike parts.

he present invention relates to a car bureter, the purpose of the invention being to arrange the carburetor so as to get the necessary mixture of air and vaporized fuel for proper combustion at all speeds.

In carbureting liquid fuel, the vacuum created by the piston stroke of the engine is depended upon to mix the fuel with the air, and it is obvious, therefore, that the amount of fuel sucked in will be varied by' the manipulation of the throttle in controlling the engine speed. In the carburetor us ordinarily constmicted, in which the liquid fuel is supplied through a permanently adjusted nozzle, it is necessary to adjustithe valve which controls the orifice of said hozzle so as to obtain sufficient gasolen or other liquid fuel to impregnato the air at the highest speed, the result being that when the speed is cut down the mixture heron-les too rich, and the operation of the engine, therefore, defective.

In accordance with the invention, the carbureting chamber, which is provided with an air inlet controlled by an automatic valve adapted to increase the' capacity of the air inlet as the vacuum increases, and is also provided with two inlet ducts for the liquid fuel, one of said ducts beingprovided with moans for making a preliminary adjustment in order to supply suflicient fuel to give the proper mixture at low speeds, while the other is variable in capacity, being normally closed, but adapted to open and increase the` extent of opening as the vacuum increases, due to the opening ofthe throttle to speed up the motor.

For convenience in description, I will refer to the fuel as gasolene, and to the two inlets for the fuel as needle valv'es, and the needles which controlthe valves :1s-the high speed and low speed needles, respectively.

Figure 1 is a. top plan View of the oarbureter embodying the invention; Fig. 2 is a The corbureter embodying the invention is provided with the float chamber or reservoir c which is supplied with gasolene through the inlet passage a2 controlled by a tapered valve o3 shown as connected with the end of a lever 0,4 'iivotod at a und connecized at its opposite end with the float which is arranged to close the valve a3 when the gusolene stands at the proper level. The float consists, us shown in F ig. 3, of upper and lower members l) and 7) connected together by means of a stein b3 which is shown as guided ut its lower endI in a socket in thel bottom of the reservoir. The member b2 is arranged to he of substantially the same specific gravity as that of the gasolene so that when submerged in the frasolene it vWill practically balance and tend to maintain the vulve in Whatever position Vit may be in. ThisI loaves the upper portion b but slightly submerged when the float is in action, and the surface tension of the liquid acting` on the snid upper member, has a strong tendency to steady the float aLl prevent the suine from osm'llating` owing to the jarring of the machine. From the float chamber a the fuel passes through a duct @from which it passes, as will be described, into the carlmrctinp,r chamber d which is herein shown as lnrvinpr a tubular outlet passage cl2 adapt- .ed to be coupled directly to the intake of the engine and provided with throttle vulve (Z3 tion.

Thel float so adjusted that the gasolene a butterfly after the usual construc- Will normally stand about on a level with the outlet port-ions of the outlet ducts 02 and so that a current of air passing into the carburcting chamber will suck up su'icient gasolone to form the necessary explosive mixture.

The outlet passage c2 is controlled byfa needle valve, the needle c of which w'ill be hereinafter referred to as the lou speed needle. The said needle c is provided with a screw threaded portion e2 and a knurled knob c for adjusting purposes. In adjusting the carbureter the low spoed needle is turned until the capacity of tho outlet 02 is just sufficient to afford the necessary mixl ture to supply the engine at the lowest speed channel g formed at which it is practicable to start and run it. The air is Supplied to the carbureting chamber d throu h an intake passage which iscontrolle by an automatic valve g, which is herein shown as a cylindrical valve located in a verticalcylindrical passage g transverse to the inlet passage f. The sa1 valve g is rovided with transverse artitions gan g* between which the wal s are cutaway to aiord a wide 'space g, the upper portion of which communicates with a underneath a lateral extension g' which projects into the carburetingFchamber d and normally lies, as shown in 2 and 3 upon the lower'surface of said c amber where the solene ducts are located. In this norma position of the valve g, the partition g' is above the wall portion of the intake f, so that a small passage is continually open from the intake to the interior of the mixing chamber. The location of the projecting portion g1 is such, moreover, that the current ofair rushing in under the said portion during the suction stroke of the piston is directed past the gasolene orifices, the orifice c', as previously described, being continually open and a justed to supply sufficient iliolene to im re nate the amount of air a itted thi-ou t e restricted assage above described. hen, however, t e suction is increased in response to increased openin of the throttle, the vacuum reduced will cause a relative increase o atmospheric pressure which will act on the under side of the parttion g*, which fits in the lower part of the c lin rical guide passage g and tends to 'it ,the valve g, thus exposing a greater portion of the opening g" and increasing the area of the air inlet to the carbureting chamber. The lower end of the guide cylinder g" is provided with a vent g to admit atmosp iedwill be heric pressure. Under these conditions, it 1s necessary to increase the amount of gasolene in order to obtain the proper mixture, and for Ithis purpose the gasolene oriiice c which is controlled by the igh speed needle h, is arranged to be opened as thevalve q rises, it being practicable to connect the hig speed needle directly with the valve g, as herein shown. Since the needle h is tapered, it is obvious that the increase in the capacity of the gasolene outlet controlled thereby will be progressively increased as the valve g o ens, so that the amount of gasolene suggoperly proportioned to t n amount of air awn into the cylinder. Converselyfwhen the throttle is closed to reduce 4the speed of the engine, the valve g will correspondingly move back to its normal osition, closing the orice controlled by t e high speed needle h, the gasolene being then supplied solely by the orifice controlled by .the low speed needle e, so that the proper mixture is alforded to keep the en' 'ne running at a low speed. The lifting e ect of the atmospher'c pressure on the valve g may, if desired, justing purposes, as herein shown, formed in the side this being accomplished, by means of4 a by-pass t Fig. 3, one end of said by-pass communicating with the carbureting chamber and the other end with the space below the artition Communication is thus varied etween t e s ace above the valve where the air is artia y exhausted and the space below t e valve which is su jected to atmospheric pressure, thus re'- ducing the eiect ofthe atmospheric pressure to some extent. By providin the said passage therefore with an a justable valve a, uw iiaing erica may be varied, as aesired.-

What I claim is: l

1. A carbureter having a carbureting chamber provided with an air inlet and two fuel ducts leading into said chamber, combined with means for making a preliminary adjustment of the capacity of one of said ducts; and means for automatically varying the capacity of the pressure of the bursting chamber.

2. A carbureter 'having a carbureting chamber provided with an air inlet and two fuel ducts leading into said chamber, combined with means for adjusting the capacit for one of said ducts, said duct, after adx justment, having a constant capacity; means for automatically varying the capacity of the other duct in response to the pressure of the air entering the carbureter chamber; and means or varying the capacity of the outlet from said carbureting chamber.

3. A carbureter aving a carbureting chamber rovided with inlet and outlet passages; a t ottle valve in the outlet passa e; an adjustable fuel valve located in the in et passage, said fuel valve after adjustment 'avin a constant capacity; a valve member contro in the inlet passage suppl o air drawn into the carbureting cham er, said valve operating automatically to increase the area of the air inlet in response to the piston suction ofthe engine; a second fuel valve also located in the inlet passage; an means for automatically varying the ca acity of said second valve in response to t e movement of the valve member controlling the inlet passa 4. In a carbureterz a car lureting chamber provided movable transversely across said inlet passage and located in a cylindrical'recess forniinag part of the carbureting chamber, y ve having a lateral orifice a portion of which is normally closed by' the wall of the cylindrical passage; "a gasolene orifice leadair` entering the carthe other duct in response toto regulate thev with an inlet passage; a valvev be varied for adof. the casting and shown d 'in full and dotted lines,

said

ing tothe carbureting chamber; a tapered name to this specification in the presence of needle conieote with1 said vzixlve to vary the two subscribing witnesses. capacity o sai gaso ene ori ce in response tothe movement of said valve; and a, sec- WILLIAM SCOTT 5 ond gasolene orifice the capacity of which Witnesses:

is nontrolled by a xed needle. M.' CovENEY,

"II testimony whereo I have signed my JAS. J. MALONEY. 

